This invention relates to an automatic security system, and more particularly to an automatic security system including a central controller that communicates with insertion-type magnetic card readers as well as proximity-type card readers.
Automatic security systems are well-known and in widespread use. Such systems typically include a central controller connected to a plurality of card readers that are located remotely from the central controller. The card readers may be connected directly to the central controller, or may be connected via multiplexers. A number of remote card readers may be located at various entrances of a building and connected to the central controller. In order to gain access to the building, a person must present an identification card to one of the remote readers, which communicates with the central controller to determine whether the person who presented the identification card is authorized to enter the building. If the person is authorized to enter, the central controller transmits a signal to the remote terminal, which electronically unlocks the door so that the person may enter. Such security systems are described in more detail in U.S. Pat. Nos. 4,095,739; 4,097,727; 4,155,073; 4,216,375; 4,218,690; 4,538,056; and 4,544,832.
The security systems described in the patents listed above utilize insertion-type card readers. This type of card reader is activated by the insertion of a plastic card having magnetically encoded data thereon. The data includes an identification code that is read by the card reader, and if the identification code is one of the codes listed in the memory of the central controller, access is granted. Insertion-type magnetic card readers, which are in widespread use, are described in more detail in U.S. Pat. Nos. 3,588,397; 3,612,788; 3,634,657; 3648,021; 3,686,479; and 3,780,268.
Similar security systems as those described above utilize proximity-type card readers instead of insertion-type readers. Proximity-type card readers do not require the insertion of a card; the card must only be brought within a predetermined distance of the proximity reader, which will then sense the presence of the card and authorize or deny access based upon data that is transmitted from the card. Such proximity-type card readers are well-known and commercially available from Identification Devices, Inc. of Boulder, Colo.
The security systems which utilize insertion-type card readers cannot be used with the proximity readers described above, and security systems used in connection with proximity readers are not able to support insertion-type card readers.